Exemplary embodiments of the invention relate to a composite profile for doors, windows or façade elements.
Such composite profiles for doors, windows or other façade elements are known from the state of the art. Thus, a composite profile which has a first and a second metallic exterior profile each with at least one hollow chamber is disclosed in German patent document DE 20 2013 105 101 U1. A middle profile made from a metallic material is located between the two exterior profiles. The metallic middle profile is connected to first exterior profile by one or more spaced insulating bars and is likewise connected with the second exterior profile by at least one or more spaced insulating bars so that good thermal insulation is achieved and relatively long protection against the transmission of flame in the event of fire is achieved.
A preferred—but not constraining—area of application for such composite profiles which have more than two metallic profile sections is for use as door profiles in the interior of buildings with special fire protection requirements.
In composite profiles for doors, windows or façade elements with insulating bars, increases or decreases in temperature on one side, such as those occurring as a result of seasonal variation, lead to shearing stress between the components of the composite profile. As a result of the shear strength of the composite profile, the shearing stress leads to the deformation of the composite profile, resulting in a curvature towards the warmer side of the composite profile. Such deformations can interfere with the function of the door or window frame constructed from the composite profile.
In particular, for relatively long composite profiles used as the frame bars for doors, the temperature-related deformation of the composite profiles has a negative effect on the functioning of the sealing and locking systems.
Solutions are known from the state of the art that address the prevention or mitigation of such stresses and deformations of composite profiles. Thus, European patent document EP 0 829 609 A2 suggests that the shear strength is low, tends towards zero or a sliding guide is present in insulating bars connected to an interior and exterior profile.
According to German patent document DE 20 2007 004 804 U1, an insulating strip has at least two or more insulating strip sections or parts, which move in relation to one another and which are connected to each other by means of bars, wherein the bars are designed such that the two insulating strip parts of the insulating strip can move relative to one another to a limited extent such that bars and the insulating strip parts which are adjacent to one another can swivel into a parallelogram shape in the movement.
German patent document DE 10 2013 204 693 A1 suggests that an insulation bar comprising two sections that slide in relation to one another, used to connect two metal profiles of a thermally insulated composite profile, is designed such that the insulation bar has means, intermittently or across a greater length of the insulation bar, of establishing a locally shear-resistant connection between the two sections of the insulation bar that nonetheless has reduced overall shear strength so that equalisation of the dilation movements is also possible here.
The disadvantage of the solutions from the state of the art is that the design for the insulating bars between the profiles with low or non-existent shear resistance results in a relatively low geometric moment of inertia.
As a result, the permissible static loads for a composite profile according to the state of the art with non-existent or low shear resistance insulating bars are lower than for composite profiles with rigid insulating bars. This results in a disadvantage when such composite profiles are used e.g., for glass facades as well as for large windows or doors so that a more extensive composite profile with non-existent or low shear resistance insulating bars needs to be used for the same static requirements in comparison with a composite profile with rigid insulating bars.
This results in a smaller glazing area and lower incidence of light for a composite profile with non-existent or low shear resistance insulating bars than for a composite profile with rigid insulating bars for the same wall opening area.
In addition, the thermal insulation properties of a composite profile with non-existent or low shear resistance insulating bars according to the state of the art are poorer than those of composite profiles according to the state of the art which have more than two metallic profile sections.
Accordingly, exemplary embodiments of the invention are directed to providing a class-specific composite profile for doors, windows or similar that at least reduces this problem.
According to an exemplary embodiment the two insulating bar zones have different shear strengths orthogonal to the cross-sectional plane of the composite profile. This can be realised through the provision or establishment of a rigid connection between all of the elements that are connected to one another in the first insulating bar zone (this includes single part insulating bars or multi-part insulating bars with their insulating bar sections and the adjacent metal profiles, so the middle metal profile and the corresponding exterior metal profile or exterior profile), while the shear strength of the elements connected to one another in the second insulating bar zone (insulating bars, metal profiles or insulating bar sections) is lower than in the first insulating bar zone at least partially or in sections.
In this way, the invention creates a composite profile for doors, windows or similar that ensures deformation of the profile as a result of temperature influences due to the differing shear strengths of the insulating bar zones and preferably in particular a shear-free or low-shear design of an insulating bar zone. Despite the reduced shear strength design of one of the two insulating zones, the result here is a surprisingly high stiffness of the composite profile.
The reduction of the shear strength in one of the two insulating bar zones can be realised in various different ways. Reference should initially be made to European patent document EP 0 829 609 A2, which discloses the basic fundamental principles of reduced shear strength. Variants of the concepts of this document are shown in German patent documents DE 10 2004 038 868 A1, DE 10 2013 204 693 A1, EP 1 004 739 B1, and DE 199 62 964 A1. The zone with reduced shear strength can be designed as in these documents. It can therefore be designed as a sliding guide that is formed between the insulating profile and one or both adjacent metal profiles. The sliding guide can also be formed between two insulating profile sections. The friction in the sliding guide must not tend towards zero. It can even be increased again locally in the sliding guide by means for generating shear strength, but the overall shear strength here should be lower along the length of the composite profile (concerning a unit of length, for example 1 m) than in the other insulating bar zone.
The two insulating bar sections can also be made from different materials and/or be connected to one another with limited movement using crossbars or similar. Combinations of these measures and other measures to reduce the shear strength in relation to a rigid connection are also conceivable.
In the second insulating bar zone, the shear strength is higher than in the other insulating bar zone. This connection is preferably actually rigid, i.e., as a result of dilation, relative movement of the “insulating bars” or “insulating bar sections or parts” and “metal profiles” elements to be connected in the insulating bar zone is prevented in this insulating bar zone for the purposes of this document using suitable measures and means. This can be well achieved through the rolling of metal profile bars on the heads or end sections of the insulating bars and through supplementary measures such as wires with variable longitudinal thickness or a knurled wire or similar in the roll area. For the purposes of this document, however, a shear-free joint—sometimes also referred to as a low-shear joint—allows for a limited relative movement of the “insulating bars” or “insulating bar sections or parts” and “metal profile” elements adjacent to and to be connected to one another in this insulating bar zone as a result of dilation. In a beneficial design variant, the composite profile has one or more insulating bars having thickened end sections for this purpose, wherein the respective end section can have a trapezoidal, triangular or wedge-shaped, or L-shaped cross-section and the respective end section engages in a groove in the metal profile.
In a beneficial design variant, the insulating bars in the composite profile have an end section having a significantly piping-like cross-section which engages in a groove in a metal profile in order to realise a form of sliding guide. In another beneficial design variant, the insulating bars in the composite profile are made from two insulating bar sections or parts, wherein both parts of the insulating bar in the direction in which the cross-section of the composite profile extends are positively connected with one another using a piping connection. This also serves the realisation of a sliding guide. The piping connection has a piping bead and a piping tag which engages in a groove with the corresponding cross-sectional geometry.
This simply and thus beneficially creates a positive but sliding guide-like connection in the direction in which the cross-section of the composite profile extends between the insulating bars and the metal profiles or within an insulating bar which can, where necessary, easily and beneficially be developed into an almost “shear-free” connection using an agent which minimises friction. In an embodiment, the end section with a piping-like cross-section is not frictionally connected to the groove.
It is particularly beneficial to be able to apply the friction-minimising agent easily, as is the case due to a co-extruded film applied to the piping bead in the piping connection. The film of the co-extruded film, which is in contact with the groove in this case, has a particularly low friction coefficient so that an almost shear-free connection is created in the direction orthogonal to the cross-sectional plane of the composite profile.
In another beneficial embodiment of the present invention, the composite profile has at least one or more hollow chambers, wherein at least one insulating strip is used in one or more of these hollow chambers. The thermal insulation properties of the composite profile are thus simply and beneficially further improved.
In another beneficial embodiment, firebreaks are positioned instead of the insulating strips or in addition to them in other hollow chambers. The fire-protection properties of the composite profile are thus also simply and beneficially further improved. It is particularly beneficial if the firebreaks are always made from a material having properties that cause an endothermic reaction when burnt, as is beneficially the case if the firebreaks are made from a material containing water of crystallisation.
According to an alternative design, it is preferred that the two insulating bar zones I, II have the same shear strength orthogonally to the cross-sectional plane of the composite profile but which is lower than that of a rigid connection.